Adaptive bitrate streaming (ABS) is a technique used for both live and on-demand (e.g., video-on-demand (VOD)) content streaming. ABS encodes an item of content (e.g., a video file) into multiple desired bitrate streams, and segments each bitrate stream into a sequence of small chunks or segments (e.g., of seconds in length). A file, called a manifest file or playlist file, is used to specify information of available streams and variant bitrates for the item of streaming content, and also specifies the Hypertext Transfer Protocol (HTTP) locations of the chunks or segments of the item of streaming content.
One example of an ABS protocol is HTTP Live Streaming (HLS). HLS is used extensively to deliver live video streams via unicast to a multitude of client devices over Internet Protocol (IP) networks. HLS encapsulates video, audio, closed-captions, trick-play streams, and metadata associated with a video channel into media containers that typically are delivered to client devices over HTTP unicast. These HLS streams are made available to client devices at an origin server or a cache server such that the HLS streams are entirely replicated for every client device consuming the same video stream on the same network.